Miller scored from a Peter Whittingham corner in the 56th minute, but Dean ruled the goal out for a foul by Joe Mason on Crystal Palace goalkeeper Julián Speroni. It proved a crucial decision, as Cardiff will now go into the second leg, in a fortnight, trailing 1-0, without an away goal.

Replays showed that there was minimal contact on Speroni, and Mackay claimed that Dean was keen to even things up after having mistakenly given the corner in the first place. "I've seen it from various angles tonight and I know what I think: the referee's made a howler," Mackay said. "He's probably thinking: 'I've made a mistake in giving the corner, and I'm going to quickly rectify that'. If you look at it, nobody's touched the goalkeeper. Nobody's anywhere near him."

However, Mackay urged his players to forget the incident and concentrate on overturning the deficit in the second leg at the Cardiff City Stadium. The Scot claimed that the tie was still very much "game on".

"To a man, everyone I've spoken to who's seen the replays cannot believe the decision," he said. "But it's happened. It's life and you get on with it. In the last 20 minutes there were four or five good attempts on target, and we looked like the home team at times.

"It's half-time. We now go back to Cardiff City Stadium 1-0 down. What spurs us on is the belief that the players have got in their ability. The amount of chances we created tonight and the way we played, absolutely it's game on."